Shed-forming apparatus for doup weave

ABSTRACT

A shed-forming apparatus for doup weaves comprises for each warp thread pair a plate adapted to be pivoted back and forth and comprising on one side of its pivoting axis a bore for the passage of the stationary warp thread and on the opposite side of its pivoting axis slot for accommodating the wip thread. Two or more plates are connected to one another as well as to drive discs by bolts or the like positioned radially outwardly beyond the slot, the drive discs being in turn engaged by a drive rod of the shed-forming mechanism. The peripheral shape of the plates may be elliptical or ellipsoidal or it may be circular. The drive discs may also take the form of belt-driven cog wheels engaging matching teeth of a toothed belt connected to the drive means for the shed-forming plates.

BACKGROUND OF THE INVENTION

The invention relates to a shed-forming apparatus for producing a doupweave comprising at least one shed-forming plate provided with a slotfor the wip thread and a bore for the stationary thread and adapted tobe pivoted back and forth, its pivoting axis being substantially normalto the warp threads and essentially parallel to the warp plane. Suchshed-forming apparatus is described in essence in FR-PS No. 952 085(Ibanez).

OBJECTS OF THE INVENTION

It is an object of the invention to design such shed-forming apparatusin as simple as possible a manner such that a comparatively large partof the width of the fabric or the fabric over its entire width can bemanufactured in doup weave fashion, or respectively in the context ofcircular weaving looms, that the tubular fabric manufactured on suchmachines comprises an uninterrupted doup weave over its entirecircumference.

In particular, in the context of bags manufactured from tubes ofappropriate diameter by cross sewing and cutting, it is highly desirablethat the tubular wall is air-pervious and thus has a coarse meshed,sieve-like texture; however, at the same time, the yarns of the tubewall--warp threads extending in the longitudinal direction of the bagand weft yarns extending circumferentially--are required to beadequately secured against displacement in order to avoid theinadvertent formation of holes by localized mutual displacement of theyarns and the resultant dropping out of the contents (potatoes, onions,nuts or the like) from the bag. However, on the other hand, it shouldremain possible to create holes intentionally in any locality of the bagwall by shifting yarns with appropriate application of force, e.g., inorder to take samples, to be able to remove spoilt parts of the bagcontents (rotting potatoes and the like), and to close again such holesby pushing back the yarns into their original positions.

GENERAL DESCRIPTION OF THE INVENTION

In order to attain the aforesaid advantages, provision is made accordingto the invention, in shed-forming apparatus of the type defined in theintroduction, for two or more shed-forming plates to be rigidlyinterconnected by bolts or the like positioned radially outwardly beyondthe slot.

Preferably, at least one shed-forming plate is connected by the bolts orthe like to at least one drive disc. Advantageously, the drive disccomprises a pivot means for its connection to a drive rod and carries anaxle pin for its pivotal mounting in the machine structure, and thepivoting axis of the plates is disposed between the slot and the bore.Preferably, the axis of the bore for the stationary warp thread, theaxes of the bolts and the pivoting axis are essentially in a commonplane.

In a specific embodiment, at least two shed-forming plates are rigidlyinterconnected by bolts positioned outwardly beyond the slot and atleast one shed-forming plate is connected to a drive disc in the form ofa cog wheel driven by a toothed belt.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the apparatus according to the invention areexplained in the following with reference to the drawings whichillustrate a preferred working example as applied to a circular loom. Inthat context:

FIG. 1 illustrates the principle underlying the apparatus according tothe invention.

FIG. 2 illustrates a doup weave shed-forming apparatus viewed sideways(viewed in the weft direction).

FIG. 3 shows a section along line III--III of FIG. 1.

FIG. 4 shows a plan view.

FIG. 5 shows a doup fabric manufactured with an apparatus according tothe invention.

FIG. 6 shows a further embodiment of the subject in accordance with FIG.2.

FIG. 7 shows a further embodiment of the shed-forming disc in accordancewith FIG. 1.

DESCRIPTION OF SPECIFIC EMBODIMENTS

In FIG. 1, the shed-forming disc is denoted as 1. It has anapproximately elliptical circumference and is pivotal about an axis 2.Of course, it may also be of circular or other shape, e.g., angularconfiguration. On one side of the axis 2, it comprises a bore 3 for thestationary warp thread 4 and on the other side of the axis 2 itcomprises a slot 5 for the wip thread 6 of the warp. The warp threads 4and 6 are derived in the direction of the arrows drawn in FIGS. 1 and 7from warp beams or spindles which are not illustrated and in theembodiment illustrated they proceed to the lower edge of the deflectingor bag ring 7 of a circular loom. The tubular fabric 9 formed byinserting the weft yarns by the shuttle in the respectively open shed 8is deflected upwardly and is, for example, rolled up after being laidflat.

The two warp threads 4 and 6 which, in FIG. 1, come in from the rear ofthe shed-forming plate 1, have passed through the bore 3 or respectivelythrough the slot 5 to form a shed 8 in the terminal position of plate 1as illustrated in FIG. 1 which is limited above by the stationary yarn 4and below by the wip thread 6 which, as illustrated in FIG. 1, liesbehind the thread 4. After the entry of the weft yarn S, the plate 1 isturned by at least 90° counterclockwise by the control device still tobe described--The position then taken by plate 1 is illustrated inbroken lines in FIG. 2. The wip thread 6 is first lifted and raisedabove the stationary thread. Approximately midway through the pivotingmovement of plate 1, wip thread 6 crosses over stationary thread 4. Atthe end of the pivoting movement of the plate 1, wip thread 6 has slidto the opposite end of the slot 5 and once again forms the lowerlimitation of the shed 8, but now lies in front of the stationary thread4. In doing so, it has carried out a "twist," preferably a "half-twist,"and after the insertion of the weft yarn S into the shed 8 is movedagain to the other side of the stationary yarn. This causes theformation of a doup fabric as illustrated in FIG. 5.

For the production of tubular fabrics in doup weave on circular looms,pluralities of shed-forming plates 1 are assembled in groups 10. Theinterconnection of the plates 1 is, for example, brought about by spacermembers 11, radially outwardly positioned of the slots 5 of the plates 1and, for example, connected by means of threaded bolts 12 (FIGS. 1, 3A)to the plates 1 (in FIGS. 3 and 4, for example, four per group 10). Itshould be clear from FIG. 4 that groups 10 may positioned concentricallyat angular locations around the rotating axis of a drum of a circularloom and connected to the drum in a manner which will be described. Forpivotal mounting and driving, two drive discs 13 are provided in theillustrated working example which are located by virtue of a shorterspacer member 14 outwardly of the discs 1 and which by the use ofpartial spacer members 15, 16 instead of a spacer member 11 areaccommodated between two plates 1. The four plates 1, the two drivediscs 13 and the spacer members 11, 14, 15, 16 thus are combined in asingle rigid structure. From each drive disc 13, a pivoting pin 17projects. These pivoting pins are mounted in bores 18, e.g., by means ofball bearing 17' of supports 20 fixed to the loom structure 19.

For driving the twist device, each group 10 comprises a slider means 21which is movable up and down in the loom structure (arrow P) along guidemeans, which are not illustrated, comprising a guide roller 22,preferably a sliding block which engages into the guide groove 23 of thegrooved drum 24 of the circular loom. The shed-forming plates 1 arepivoted back and forth by control rods 25 linked at one end to theslider means 21 and at the other end to the drive discs 13, and thus thedoup fabric is formed in the manner already described.

The peripheral configuration of the plates can be selected optionallyand may be elliptical or ellipsoidal as illustrated or in its simplestform may be circular.

Naturally, a variety of modifications are possible within the scope ofthe invention. Thus, it is possible for the drive disc 13 to take theform of a cog wheel as shown in FIG. 6 which meshes with a toothed belt25' which, on the one hand, is fixed to the slider member 21 and, on theother hand, embraces the cog wheels 13 over about half theircircumferences, meshing with the teeth thereof. This causes theshed-forming plates 1 to be pivoted to and fro, causing the formation ofthe doup fabric as described further above. In this context, the toothedbelt is fixed to the slider member 21 and guided over return rollers 26acted upon by springs 27 whereby the belt 25' is always kept tight.

It is furthermore possible to provide the cog wheel only with teeth overthat peripheral region which enters into contact with the toothed belt,and vice versa the toothed belt 25' need only be provided with teethover that part of its length which has to mesh with the teeth of the cogwheel.

It is furthermore possible to provide the shed-forming plates 1, inparticular, if they are of circular configuration with toothedformations on their peripheries or such parts thereof which mesh withthe teeth of the toothed belt 25'. In that case, the drive discs 13 maybe dispensed with and preferably the marginal shed-forming plates 1 ofthe groups 10 will then carry the axial pins 17 which are mounted in thesupports 20.

The shed-forming disc 1 can have the form of a wire frame as shown inFIG. 7 which encloses or defines a slot 5 for the wip thread and has anelliptical circumference and is pivotal about the axis 2. The frame isin the form of a wire from which lateral tongues 1', 1" project, one ofwhich, e.g., 1', carries the axis 2 and has a bore 3 for the stationarythread 4. The frame 1 can be enclosed by stiffening wire frame IA, whichcan have an elliptical, circular or other form, e.g., angularconfiguration, and is connected with two opposite points, e.g., in casethe frames 1, 1A have an elliptical shape, at the narrow sides asdesignated by points lB. In this case, the tongues 1', 1" extendpreferably between both frames 1, 1A; however, they may laterallyproject beyond frame 1A, too. The frame 1A is preferably composed, as isframe 1, of a suitable resistant wire.

It is further possible to provide a belt-drive cog wheel which isconnected or coupled with the shed-forming disc and which is meshingwith the toothed belt 25' instead of providing the shed-forming disc asincluding a cog wheel.

What we claim is:
 1. Shed-forming apparatus for producing a doup weavecomprising shed-forming means, each of said shed-forming means providedwith a slot for accommodating and lifting a wip thread and a bore foraccommodating a stationary thread and adapted to be pivoted back andforth, about a pivoting axis substantially normal to the wip thread andthe stationary thread and essentially parallel to a warp plane, at leasttwo of said shed-forming means being rigidly interconnected at positionslocated outwardly of the slot to a group of said shed-forming means, aplurality of groups being positioned concentrically and at angularlocations around a rotating axis of a drum of a circular loom andconnected to the drum so that each of said groups are pivoted byrotation of said drum.
 2. Apparatus according to claim 1, wherein theshed-forming means consists of at least one shed-forming plate ofelliptical peripheral configuration connected to at least one drivedisc, which includes a pivot for connection with a drive rod and carriesan axle pin for pivotal mounting.
 3. Apparatus according to claim 2,wherein the pivoting axis of the plates is disposed between the slot andthe bore.
 4. Apparatus according to claim 1, wherein the bore for thestationary warp thread is disposed in the region of the pivoting axis ofsaid shead-forming means.
 5. Shed-forming apparatus for producing a doupweave comprising shed-forming places, each provided with a slot foraccommodating a wip thread and a bore for accomodating a stationarythread and adapted to be pivoted back and forth, about a pivoting axissubstantially normal to the wip thread and the stationary thread andessentially parallel to a warp plane wherein two shed-forming plates arerigidly the slot, at least one shed-forming plate being connected to atleast one drive disc, the drive disc including a pivot for connectionwith a drive rod and carrying an axle pin for pivotal mounting. 6.Apparatus according to claim 5, the shed-forming plates are ofelliptical peripheral configuration.
 7. Shed-forming apparatus forproducing a doup weave comprising shed-forming plates, each providedwith a slot for accommoduating a wip thread and a bore for accommodatingstationary thread and adapted to be pivoted back and forth, about apivoting axis substantially normal to the wip thread and the stationarythread and essentially parallel to a warp plane wherein two shed-formingplates are rigidly interconnected at positions located radiallyoutwardly beyond the slot, at least two shed-forming plates beingrigidly interconnected by bolts positioned outwardly beyond the slot andat least one shed-forming plate being connected to a drive disc in theform of a cog wheel driven by a toothed belt.
 8. Apparatus according toclaim 7, wherein said cog wheel carries teeth over at least part of itsperiphery adapted to mesh with matching teeth of the driven toothedbelt.
 9. Apparatus according to claim 7, wherein the toothed belt passesaround spring-loaded deflecting rollers.
 10. Shed-forming apparatus forproducing a doup weave comprising comprising shed-forming plates, eachproviding with a slot for accommodating a wip thread and a bore foraccommodating a stationary thread and adapted to be pivoted back andforht, about a pivoting axis substantially normal to the wip thread andthe stationary thread and essentially parallel to a warp plane whereintwo shed-forming plates are rigidly interconnected at positions locatedradially outwardly beyond the slot, the shed-forming plates including afirst frame defining the slot for the wip thread and a second stiffeningframe enclosing the first frame, at least one of said frames consistingof a wire.
 11. Circular loom comprising a shed-forming apparatus forproducing a doup weave comprising shed-forming places, each providedwith a slot for accommodatng a wip thread and a bore for accommodating astationary thread and adapted to be pivoted back and forth, about apivoting axis substantially normal to the wip thread and the stationarythread and essentially parallel to a warp plane wherein at least two ofthe shed-forming plates are rigidly interconnected by bolts posiitonedradially outwardly beyond the slot, at least one of said shed-formingplates being connected to at least one drive disc, the drive discincluding a pivot for connection with a drive rod and carrying an axlepin for pivotal mounting.